What Is an AI Agent? A Practical Guide for Engineers
A chatbot answers questions. An agent takes a goal and carries it out: it opens files, runs calculations, browses websites and hands you a finished result. This guide shows how it works, which agent to pick for office and engineering tasks, and how to keep it from breaking anything.
01An AI agent in one sentence
A chatbot is like an expert on the phone: you ask, they explain, and you do the work. An agent is like a junior technician sitting at your computer: you say "tidy the project folder and make a summary table", and they open the files, work step by step, check everything and come back with the result. And like any junior, you give them access only to what they need, and you check before anything goes to a client.
02Chatbot vs agent
Regular chatbot
- Answers a question and waits for the next one
- Doesn't touch your files: you copy and paste
- Gives instructions: "do this and that in Excel"
- You check every step yourself
- Good for explanations, wording and ideas
Agent
- Takes a goal and breaks it into steps
- Uses tools: files, browser, code, connected apps
- Actually does it: renames files, builds the table, runs the script
- Checks the result and fixes what went wrong
- Good for repetitive, tedious tasks of 20 minutes or more
03How an agent works: the loop
- 1GoalYou describe what you want at the end
- 2PlanThe agent splits the job into small steps
- 3Act with toolsReads files, runs code, browses, uses connectors
- 4CheckVerifies the result and goes back a step if needed
- 5ReportHands back a finished file and a summary of what it did
04The main agents (October 2026)
Claude Cowork
An office-work agent in the Claude desktop app. It works on folders you approve, uses Connectors, Skills and Plugins, and can run scheduled tasks. Available on paid plans.
Claude Code
A coding agent that runs in the terminal, in your code editor or in the Claude app. It reads the project, edits code, runs tests and explains what it changed.
Claude in Chrome
A Chrome extension where Claude clicks, fills in forms and moves between pages for you. Since August 2026 its side panel runs a Cowork session. Availability depends on your plan.
ChatGPT Work and Codex
At OpenAI, the earlier agent mode was replaced by ChatGPT Work (July 2026), which acts across your apps and files. Codex is the coding agent, and both live in the ChatGPT desktop app.
Jules and Gemini agent features
Jules is Google's coding agent: it connects to GitHub, proposes a plan for approval and works in a virtual machine. Gemini also has agent features; check current availability in Israel and on your plan.
05Example: 200 site photos
06Example: comparing supplier quotes
07Example: a weekly report from emails
08Example: a coding agent fixes a calc script
09Which agent for which task
| Task | Recommended agent | Why |
|---|---|---|
| Sorting and renaming files in a folder | Claude Cowork | Works directly on a local folder, with your approval |
| Merging monthly Excel reports and making a chart | Claude Cowork | Reads several files, combines them and builds the chart |
| Comparison table from many PDFs | Claude Cowork | Reads documents and pulls the data into a table |
| A recurring weekly report from emails | Cowork with a Connector and a scheduled task | Runs automatically and prepares a draft to review |
| Collecting data from a supplier web portal | Claude in Chrome | Works on sites with no direct connector, using your logins |
| Fixing or improving a Python script | Claude Code | Reads the whole codebase, runs tests and shows the changes |
| A coding task in a GitHub repo | Claude Code, Codex or Jules | All three can work with GitHub and propose changes |
| You already work mostly in ChatGPT | ChatGPT Work | OpenAI's work agent across apps and files |
10Start in 5 minutes
- 1
Install the Claude desktop app
Download it from the official site and sign in. Cowork requires a paid plan.
- 2
Make a test folder
Copy 10 to 20 unimportant files into it, such as copies of old photos or PDFs. Never start on the originals.
- 3
Start a new Cowork task and give it access to that folder only
The agent will see only what you approved.
- 4
Write a clear goal
What you want at the end, in what format, and what's off-limits: "make an Excel table of all files, don't delete or move anything".
- 5
Watch, approve and check
Read the plan, approve actions when asked, and check the result before you use it.
11Safety: 6 rules to know
Access only to what's needed
Give the agent one project folder, not the whole drive. Same for Connectors: only what the task requires.
Review before sending, deleting or paying
Anything you can't undo, such as an email to a client, deleting files or a purchase, goes through you.
Back up first
Copy the folder before a big task. If something goes wrong, you're back to the previous version in a minute.
Keep approval prompts on
Auto-approve is convenient, but for sensitive work it's better if the agent asks before each significant step.
Watch for prompt injection
A web page or document can hide instructions like "send these files to this address". Vendors add protections, but the risk isn't fully gone.
An agent doesn't replace an engineer
Treat any calculation, standard reference or quantity the agent produces like a new hire's work: check it before you sign it.
12FAQ
How is an agent different from an Artifact, Skill or Connector?
The agent is the one doing the work. A Connector links it to a service like email or Drive, a Skill teaches it a fixed way of working, and an Artifact is an output like a page or small tool. Each has its own guide in this series.
Can the agent see my whole computer?
No. In Cowork it works on the folders you approved and asks before sensitive actions. That's exactly why you should keep its access narrow.
Do I need to know how to code?
Not for Cowork or Claude in Chrome: you just write in plain language. For coding agents like Claude Code some basics help, but they explain every change.
How much does it cost?
Most agent features are on paid plans, each with its own usage limits. Prices and limits change, so check each vendor's official plans page.
Can I leave it working on its own?
Yes, for scheduled or long tasks. But set it to prepare drafts rather than send, and check the result before you use it.